Resonant Converter Multi-mode Control for Low-load Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switched-mode power converters experience inefficiencies and increased power consumption during low-load conditions due to the need for burst mode operation, which can result in high power consumption and inefficiencies when no load or very light load conditions are detected.
Innovation Solution
A method of controlling a switched-mode power supply by generating a feedback signal proportional to its output and operating in a normal mode, adjusting the pulse modulated signal to regulate the feedback signal to a first signal level, and transitioning to a second operating mode by adjusting the dead-time of the pulse modulated signal when the feedback signal crosses a threshold, thereby optimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional switched-mode power converters operate in burst mode during low-load conditions, then they can maintain output voltage regulation, but they experience high power consumption and inefficiencies
Solution Approach 1:
The patent applies dynamics by making the switching frequency variable rather than fixed. The controller dynamically adjusts the switching frequency based on load conditions, allowing the converter to operate efficiently across different power levels. During low-load conditions, the frequency is reduced to minimize switching losses while maintaining adequate output regulation, whereas during high-load conditions, the frequency increases to handle the higher power demand.
Solution Approach 2:
The patent changes the operating parameters of the power converter, specifically the switching frequency and duty cycle, to optimize performance under different load conditions. By continuously adjusting these parameters based on feedback from the output voltage and current sensors, the system maintains efficient operation across the full load range, avoiding the high power consumption associated with fixed-frequency burst mode operation.
2Loss of energy
If the switching frequency is reduced during low-load conditions, then switching losses are minimized, but output voltage regulation becomes more difficult to maintain
Solution Approach 1:
The patent employs feedback control by continuously monitoring the output voltage and comparing it with the reference value. The error signal generated from this comparison is used to adjust the duty cycle and switching frequency in real-time. This closed-loop control ensures that even when the switching frequency is reduced to minimize losses, the output voltage regulation is maintained within acceptable tolerances through dynamic parameter adjustment.
Solution Approach 2:
The system dynamically adapts the switching frequency and duty cycle based on the instantaneous load conditions and output voltage requirements. During low-load conditions, the frequency is reduced to minimize switching losses, while the duty cycle is adjusted to maintain proper voltage regulation. This dynamic adaptation allows the system to optimize the trade-off between switching losses and voltage regulation performance.
3Use of energy by moving object
If burst mode operation is used during no-load conditions, then the converter can reduce power consumption, but it generates high ripple and inefficiencies
Solution Approach 1:
The patent uses periodic action by implementing discontinuous conduction mode (DCM) operation during light-load conditions. Instead of traditional burst mode with long off-periods, the converter operates in DCM where the inductor current naturally reaches zero during each switching cycle, creating a softer periodic action that reduces ripple generation. This periodic current waveform maintains lower RMS current and reduces electromagnetic interference while still achieving low power consumption.
Solution Approach 2:
The system changes operational parameters to transition from continuous conduction mode (CCM) to discontinuous conduction mode (DCM) under light-load conditions. This parameter change fundamentally alters the current waveform characteristics, reducing ripple and harmful emissions while maintaining efficient operation. The controller adjusts the switching frequency and duty cycle to ensure smooth transition between CCM and DCM, optimizing both ripple reduction and power efficiency.
Data Source
AI summary
In accordance with an embodiment, a method of controlling a switched-mode power includes generating a feedback signal proportional to an output of the switched-mode power supply, and operating the switched-mode power supply in a normal mode. If the feedback signal crosses a first threshold, the switched-mode power operates in a second operating mode. In the first operating mode the pulse modulated signal is adjusted to regulate a feedback signal to a first signal level, and in the second operating mode, a dead-time of the pulse modulated signal is adjusted to signal to regulate a feedback signal to a second signal level different from the first signal level. The method further includes driving a switch of the switched-mode power supply with the pulse modulated signal.